His61 and His79 act as acid catalysts for the stereospecific elimination of the 4a(R)- and 4a(S)-hydroxyl groups, respectively. The role of His62 is primarily binding substrate with additional component of base catalysis

the enzyme is identical with the dimerization cofactor DCoH, a cofactor for the hepatocyte nuclear factor 1alpha, HNF1alpha, which is essential for expression of phenylalanine hydroxylase PAH EC 1.14.16.1

PCD deficiency causes in newborns a mild form of hyperphenylalaninaemia with persistent high urinary levels of primapterin. Affected patients appear completely normal, but have elevated phenylalanine levels at birth, which normalize after few months of life and remain normal or just above the normal range of phenylalanine with an unrestricted diet

the bifunctional protein shows two disparate functions, i.e. dimerization cofactor of HNF-1, DCoH1, and pterin-4a-carbinolamine dehydratase, PCD, that are associated with a change in oligomeric state between dimer and tetramer, overview. The PCD activity of homotetramers aids in aromatic amino acidmetabolism

dehydratase/DCoHalpha, has the kinetic properties necessary for regenerating tetrahydrobiopterin cofactor for phenylalanine hydroxylase. Properties of dehydratase/DCoHalpha are consistent with the hypothesis that the activity of this isozyme could account for the relatively mild symptoms reported for patients with a defect in dehydratase/DCoH

both PhhB and phenylalanine hydroxylase (PhhA) are induced coordinately in the presence of either L-tyrosine or L-phenylalanine, but PhhB exhibits a significant basal level of activity that is lacking for PhhA. PhhA and PhhB form a protein-protein complex

the enzyme is essential in vivo to prevent rearrangement of 4a-hydroxy-6(R)-tetrahydrobiopterin and to maintain the supply of tetrahydrobiopterin cofactor for hydroxylases under conditions where the nonenzymatic rate would be inadequate

dehydratase/DCoHalpha, has the kinetic properties necessary for regenerating tetrahydrobiopterin cofactor for phenylalanine hydroxylase. Properties of dehydratase/DCoHalpha are consistent with the hypothesis that the activity of this isozyme could account for the relatively mild symptoms reported for patients with a defect in dehydratase/DCoH

both PhhB and phenylalanine hydroxylase (PhhA) are induced coordinately in the presence of either L-tyrosine or L-phenylalanine, but PhhB exhibits a significant basal level of activity that is lacking for PhhA. PhhA and PhhB form a protein-protein complex

the enzyme is essential in vivo to prevent rearrangement of 4a-hydroxy-6(R)-tetrahydrobiopterin and to maintain the supply of tetrahydrobiopterin cofactor for hydroxylases under conditions where the nonenzymatic rate would be inadequate

by affinity chromatography over a HisTrap nickel chelating column, followed by TEV cleavage/dialysis at 4°C overnight and then further passage over the a HisTrap nickel column to remove the tag, contaminants and the His-tagged TEV protease. A final purification step using a Superdex 75 size-exclusion column is performed

expression in Escherichia coli BL21 (DE3). There is a high degree of structural similarity between Toxoplasma gondii PCD and the mammalian orthologue, Rattus norvegicus PCD, which is identical to the human enzyme

the His79Ala mutant and the His79Ser mutant exhibit about 40% the activity of the wild-type enzyme. In the mutant enzymes His61Ala and His62Ala the activity is reduced to 10%. In the mutant enzymes Asp60Ala and Arg87Ala the activity is reduced to 30%. The Glu57Ala mutant and the His61Ala,His62Ala double mutant show no activity

the His79Ala mutant and the His79Ser mutant exhibit about 40% the activity of the wild-type enzyme. In the mutant enzymes His61Ala and His62Ala the activity is reduced to 10%. In the mutant enzymes Asp60Ala and Arg87Ala the activity is reduced to 30%. The Glu57Ala mutant and the His61Ala,His62Ala double mutant show no activity

the His79Ala mutant and the His79Ser mutant exhibit about 40% the activity of the wild-type enzyme. In the mutant enzymes His61Ala and His62Ala the activity is reduced to 10%. In the mutant enzymes Asp60Ala and Arg87Ala the activity is reduced to 30%. The Glu57Ala mutant and the His61Ala,His62Ala double mutant show no activity

the His79Ala mutant and the His79Ser mutant exhibit about 40% the activity of the wild-type enzyme. In the mutant enzymes His61Ala and His62Ala the activity is reduced to 10%. In the mutant enzymes Asp60Ala and Arg87Ala the activity is reduced to 30%. The Glu57Ala mutant and the His61Ala,His62Ala double mutant show no activity

the His79Ala mutant and the His79Ser mutant exhibit about 40% the activity of the wild-type enzyme. In the mutant enzymes His61Ala and His62Ala the activity is reduced to 10%. In the mutant enzymes Asp60Ala and Arg87Ala the activity is reduced to 30%. The Glu57Ala mutant and the His61Ala,His62Ala double mutant show no activity

the His79Ala mutant and the His79Ser mutant exhibit about 40% the activity of the wild-type enzyme. In the mutant enzymes His61Ala and His62Ala the activity is reduced to 10%. In the mutant enzymes Asp60Ala and Arg87Ala the activity is reduced to 30%. The Glu57Ala mutant and the His61Ala,His62Ala double mutant show no activity

the single mutants H73A and H74A and the double mutant H73A,H74A are completely inactive. The activity of the mutant enzymes H91A and E69A is 40% of the activity of the wild type enzyme. The activity of the mutant enzymes D100N is 10% of the activity of the wild type enzyme

the single mutants H73A and H74A and the double mutant H73A,H74A are completely inactive. The activity of the mutant enzymes H91A and E69A is 40% of the activity of the wild type enzyme. The activity of the mutant enzymes D100N is 10% of the activity of the wild type enzyme

the single mutants H73A and H74A and the double mutant H73A,H74A are completely inactive. The activity of the mutant enzymes H91A and E69A is 40% of the activity of the wild type enzyme. The activity of the mutant enzymes D100N is 10% of the activity of the wild type enzyme

the single mutants H73A and H74A and the double mutant H73A,H74A are completely inactive. The activity of the mutant enzymes H91A and E69A is 40% of the activity of the wild type enzyme. The activity of the mutant enzymes D100N is 10% of the activity of the wild type enzyme

the single mutants H73A and H74A and the double mutant H73A,H74A are completely inactive. The activity of the mutant enzymes H91A and E69A is 40% of the activity of the wild type enzyme. The activity of the mutant enzymes D100N is 10% of the activity of the wild type enzyme

the single mutants H73A and H74A and the double mutant H73A,H74A are completely inactive. The activity of the mutant enzymes H91A and E69A is 40% of the activity of the wild type enzyme. The activity of the mutant enzymes D100N is 10% of the activity of the wild type enzyme

mutant enzyme H61A shows no dehydratase activity with 4a(R)-hydroxy-6(R)-methyltetrahydropterin. Mutant enzyme H79A shows no dehydratase activity with 4a(S)-hydroxy-6(R)-methyltetrahydropterin. The Km-value for 4a(S)-hydroxy-6(R)-methyltetrahydropterin is comparable to the Km-value of the wild type enzyme. The turnover number of the mutant enzyme H62A is 24% of that with the wild type enzyme for the 4a(R),6(S)-isomer and the 4a(S),6(R)-isomer

the point mutation at the enzyme tetramer interface overcomes the dissociation barrier of the homotetramer and increases the interaction with HNF-1alpha. Presence of an ordered water molecule at the tetramer interface, which may destabilize the homotetramer

mutant enzyme C82R reveals 60% decrease in Vmax and a slight decrease in Km-value for 4a-hydroxytetrahydrobiopterin. The susceptibility to proteolysis of mutant C82R, however is markedly increased compared with the wild type enzyme

nine different mutations detected in patients with PCD deficiency. All these mutations are associated with a benign form of tetrahydrobiopterin deficiency, characterized by persistent urinary excretion of 7-substituted biopterin (primapterin or primapterinuria) and transient hyperphenylalaninemia. Most of the mutations recognized in patients with PCD deficiency are either a single amino acid change or a stop codon

Please wait a moment until the data is sorted. This message will disappear when the data is sorted.

Renatured/COMMENTARY

ORGANISM

UNIPROT

LITERATURE

DCoH2 unfolding through guanidine is reversible, kinetics, equilibrium unfolding data fit to a two-state model with no apparent intermediate, but folding intermediates are detectable. Proposal of an unfolding pathway in which the tetramer unfolds slowly, but the dimer folds reversibly